<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>DomHTML</title>
</head>
<body>
    <div id="div1">
        div
    </div>

<script>
    var div=document.getElementById("div1");

    div.innerHTML = "??:<input type='text' value='请输入'>";
    //将div中包裹的原来的内容换成这个输入框

</script>
</body>
</html>